php curl script

I'm using a script to edit the referrer which works but somehow the client ip is not being preserved and the server ip where the php code is hosted become seen as the client ip.  Am I missing something?  

<?php
$url_page = "http://www.google.com";
$user_agent = "Mozilla/4.0";
$ch = curl_init();
curl_setopt ($ch, CURLOPT_URL, $url_page);
curl_setopt ($ch, CURLOPT_USERAGENT, $user_agent);
curl_setopt ($ch, CURLOPT_HEADER, 0);
curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt ($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt ($ch, CURLOPT_TIMEOUT, 120);
curl_setopt ($ch, CURLOPT_REFERER, 'http://www.example.com/index.html');

$string = curl_exec($ch);
header("Content-type: ".curl_getinfo($ch, CURLINFO_CONTENT_TYPE));
curl_close($ch);
echo $string;
?>